The Twin Girls

Two twin girls are wondering after a biology class why they are twins and never looked alike.
Twin1: Don't you think we should ask mum and dad about it?
Twin2: I think so.
When they got home.
Twin1: Mum, are we twins.
Dad: Yeah.
Mum: I think so.
Twin2: really? :(
Twin1: That means, it was a threesome?

What is sex?

This is a conversation between a 15 years old boy and his dad
Son: Dad, what is sex?
Dad: it is not that simple to explain. It is a kind of enjoyment that gives you a sensation.
Son: Can we try it?